The matchup had originally been scheduled for ONE 172 last year but collapsed dramatically on the eve of the event, triggering a public dispute that briefly threatened Kaito’s relationship with the promotion.
Grigorian had been preparing to face the Japanese star in Tokyo when the fight fell through late during fight week, reports the Bangkok Post.
ONE Championship chairman and CEO Chatri Sityodtong initially blasted Kaito publicly, accusing the fighter of pulling out and saying he “didn’t deserve to be paid” after the bout was cancelled.
The Armenian-Belgian veteran also mocked the situation, calling the withdrawal a “disgrace” and insisting he was ready to fight anyone – including Japan’s Masaaki Noiri – on short notice.
The dispute escalated when Kaito demanded a public apology from the promotion.
Chatri later walked back his comments, admitting they had been inappropriate and smoothing over tensions with the Japanese star.
Kaito subsequently made his ONE Championship debut later that year but suffered a unanimous decision loss to Iran’s Mohammad Siasarani.
Since then, the 28-year-old has returned to form in Japan, most notably defending his KNOCK OUT title with a victory over former ONE star Sitthichai Sitsongpeenong.
Grigorian, meanwhile, had been pushing for another shot at featherweight kickboxing gold.
The 33-year-old Armenian striker was targeting a title fight against champion Superbon following their respective wins at ONE 173 in Tokyo last November, also at Ariake Arena.
Those plans now appear to have shifted, with Grigorian instead facing Kaito in what could serve as a key contender bout in the division.
The matchup adds further firepower to the promotion’s return to Tokyo.
ONE Samurai 1 will launch ONE Championship’s new monthly Japanese event series and is quickly shaping up as one of the promotion’s most stacked cards of the year.
Rodtang Jitmuangnon and Takeru Segawa will headline the Apr 29 show in a rematch for the interim flyweight kickboxing world title.
Jonathan Haggerty will defend his bantamweight kickboxing title against Japan’s Yuki Yoza, while flyweight MMA champion Yuya Wakamatsu puts his belt on the line against Uzbekistan’s Avazbek Kholmirzaev.
With Grigorian and Kaito now added to the lineup, Ariake Arena is set to host another high-profile night for the promotion’s expanding push into the Japanese market.
One lingering question remains in the featherweight kickboxing division: who will challenge Superbon for the undisputed title next.
Chinese contender Liu Mengyang is widely considered a leading candidate, though no defence has yet been officially announced.